One of the new features in iOS 5 is the ability to delete music in the Music app directly on the device, by swiping to delete like you do in Mail. This is great for me because my iPhone is generally pretty full, so as I add new music/apps/podcasts, I can go back through and delete stuff I no longer listen to in order to free up space.

However - when I sync my iPhone with iTunes, it copies everything I deleted right back! It must see that I have music on the computer that I've told it to sync, recognizes that those files aren't on the device, and copies them back over.

Is it me, or is this a bug? What would be the purpose of being able to delete files directly from the device if they get copied back over every time you sync?